The airline industry's vulnerability to security breaches in the UK is under intense scrutiny. But while the events of the past few weeks have resulted in more stringent checks on passengers, what focus are airlines and airports placing on the psychological testing or profiling of their staff?

The UK airline industry recruits around 1,500 cabin crew each year. British Airways (BA) has about 13,500 cabin crew, most of whom are based at Heathrow and Gatwick. The airline has a rigorous recruitment process involving application forms, assessment centres (role plays, presentations, etc) and psychological tests, and follows the guidelines laid down by the British Psychological Society and the Chartered Institute of Professional Development.

All major airlines require candidates to provide references and details of employment history over the past five years. A would-be terrorist may have an uneven work record with a history of travel to particular locations abroad. Yet someone willing to undertake terrorism might easily provide verifiable references, together with a complete employment and educational history. So, employment dates, references and passports need to be very carefully scrutinised.

Airlines routinely make a criminal record check at "basic disclosure level" - the lowest level - containing details of convictions considered to be unspent under the Rehabilitation of Offenders Act 1974.

But if the applicant is not known to the police or security services, this process will be of little value. Indeed, there may be a pattern of good work and charitable deeds. London bomber Mohammad Sidique Khan taught special-needs children and ran a gym for disadvantaged youths. One child taught by him said: "He seemed a kind man. He taught the really bad kids and everyone seemed to like him."

Nor would an interview be an effective way of detecting terrorist intentions. Terrorist organisations could easily select a person able to make the right impression. UK airline cabin crew training agency, Ready2fly, claims its training will answer questions such as "How much information should I give?" This is concerning as the agency supplies many of the major airlines, including Virgin Atlantic, Ryanair, BA and easyJet.

BA uses psychometric tests to assess the candidate's ability, potential and personality. It says the assessment aims to "find out a bit more about you" but stresses it is not looking for a particular personality type.

Psychometric testing measures the ability or aptitude of the candidate to perform in the job applied for. It is also possible to spot conditions such as depression, as well as positive traits such as openness, being an extrovert and conscientiousness. Yet this information is being used to assess the competence of the cabin crew applicant, and not preferences for terrorist behaviour.

By contrast, psychological profiling uses a selection of tools to gather a well-rounded picture of the person. Crucially, this profiling also has techniques to detect applicants who are lying. Used properly, it has the best chance of detecting the type of personality most likely to indicate fundamentalist or terrorist inclinations. Profiling is frequently used by America's FBI, and has allowed them to identify the characteristics of those associated with particular crimes.

While the UK government has been discussing with airport authorities a passenger-profiling technique that involves selecting people who are behaving suspiciously, have an unusual travel pattern or, most controversially, have a certain ethnic or religious background, the United States is looking at an Israeli system of psychological profiling that could reveal a passenger's "hostile intent".

The challenge for psychological profiling in screening for terrorists is that such characteristics occur in relatively few people. And since the recruitment process occurs before a terrorist act, there are no clues and no crime scene to examine. There is also a real issue about how an employer could act on information without damaging civil liberties and infringing employment law.

Little is known about the psychology of terrorists, especially those likely to become suicide bombers. The phenomenon is relatively recent and isolated in the west. The Australian Institute of Forensic Psychology suggests that terrorists are usually under 30; are likely to go to great lengths to hide suspicious details about their background; repeatedly "fake good" on a test; are believed to have a low team orientation and mistrust others.

But evidence shows that the most important attribute is often devotion to their religion. Many terrorists believe killing others is acceptable and that they will be richly rewarded in the afterlife. It is also important to stress that ethnic appearance and background are certainly not indicators. An Australian-born Anglo-Celtic man has recently been convicted of training with, and receiving funds from, al-Qaida.

Terrorist organisations also use their own form of profiling in recruitment. In a programme called The Mind of a Suicide Bomber, Abul Nasser Issa, a Hamas bombmaker and recruiter, was interviewed in an Israeli prison. Asked "How do you know who is qualified to become a Shaheed? How do you convince one to blow himself up?", he responded: "You will see it in his eyes ... a Shaheed has to have the motivation to become a martyr, to have faith ... this kind of job requires strong will and persistence."

There is little empirical evidence on the psychological profile of a terrorist and any assessment would have to detect the risk of future violent behaviour before it happens. Psychological profiling is not a 100% effective and predictive tool. But it should certainly be part of the airports' and airlines' defence mechanism.

MPs have already been warned that security at British airports is not sufficient. Chief superintendent Jerry Saville, in charge of the police operations at Heathrow, said particular measures had "not kept pace" with terrorist threats. He feared thousands of staff were working in airports without undergoing proper security checks.

Giving evidence to the Commons Transport Committee, Saville questioned the rigour of employment checks of people who have access to airports. This not only included airline staff but also agency staff.

Looking ahead, London has received a glowing report from the International Olympic Committee on the preparations for the 2012 games. More than 80 volunteering organisations from across the UK have signed up to deliver 70,000 volunteers to help with the games. Sources of recruitment would include sports clubs and sports governing bodies, local volunteer centres, older people's groups and community associations.

How will such a mass of individuals be screened and selected? What are the barriers in place to prevent infiltration by terrorists?

No decision has yet been made by the Olympic Organising Committee regarding the recruitment of volunteers. For the sake of the games, it needs to be sure the voluntary sector, experienced in managing volunteers, and a likely candidate for managing the process, has the capability and expertise to tackle the task.